;;; pandoc-mode.el --- Minor mode for interacting with Pandoc  -*- lexical-binding: t -*-

;; Copyright (c) 2009-2019 Joost Kremers

;; Author: Joost Kremers <joostkremers@fastmail.fm>
;; Maintainer: Joost Kremers <joostkremers@fastmail.fm>
;; Created: 31 Oct 2009
;; Version: 2.28
;; Keywords: text, pandoc
;; Package-Requires: ((hydra "0.10.0") (dash "2.10.0"))

;; Redistribution and use in source and binary forms, with or without
;; modification, are permitted provided that the following conditions
;; are met:
;;
;; 1. Redistributions of source code must retain the above copyright
;;    notice, this list of conditions and the following disclaimer.
;; 2. Redistributions in binary form must reproduce the above copyright
;;    notice, this list of conditions and the following disclaimer in the
;;    documentation and/or other materials provided with the distribution.
;; 3. The name of the author may not be used to endorse or promote products
;;    derived from this software without specific prior written permission.
;;
;; THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
;; IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
;; OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
;; IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
;; INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
;; NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES ; LOSS OF USE,
;; DATA, OR PROFITS ; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
;; THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
;; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
;; THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

;;; Commentary:

;; Pandoc-mode is a minor mode for interacting with Pandoc, a 'universal
;; document converter': <http://johnmacfarlane.net/pandoc/>.
;;
;; See the pandoc-mode manual for usage and installation instructions.

;;; Code:

(require 'easymenu)
(require 'hydra)
(require 'dash)
(require 'pandoc-mode-utils)
(require 'cl-lib)
(require 'thingatpt)

(defvar-local pandoc--@-counter 0 "Counter for (@)-lists.")

(defvar pandoc--window-config nil
  "Stores the window configuration before calling pandoc--select-@.")

(defvar pandoc--pre-select-buffer nil
  "Buffer from which pandoc--@-select is called.")

(defvar pandoc--@-buffer nil
  "Buffer for selecting an (@)-element.")

(defvar pandoc--@-overlay nil
  "Overlay for pandoc--@-buffer.")

(defun pandoc--@-counter-inc ()
  "Increment pandoc--@-counter and return the new value."
  (when (= pandoc--@-counter 0) ; hasn't been updated in this buffer yet.
    (save-excursion
      (goto-char (point-min))
      (while (re-search-forward "(@\\([0-9]+?\\))" (point-max) t)
        (let ((label (string-to-number (match-string 1))))
          (when (> label pandoc--@-counter)
            (setq pandoc--@-counter label))))))
  (setq pandoc--@-counter (1+ pandoc--@-counter)))

(defvar pandoc-@-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map "q" #'pandoc-quit-@-select)
    (define-key map "j" #'pandoc-next-@)
    (define-key map "n" #'pandoc-next-@)
    (define-key map [down] #'pandoc-next-@)
    (define-key map "k" #'pandoc-prev-@)
    (define-key map "p" #'pandoc-prev-@)
    (define-key map [up] #'pandoc-prev-@)
    (define-key map [return] #'pandoc-select-current-@)
    (define-key map [home] #'pandoc-goto-first-@)
    (define-key map [prior] #'pandoc-goto-first-@)
    (define-key map [end] #'pandoc-goto-last-@)
    (define-key map [next] #'pandoc-goto-first-@)
    map)
  "Keymap for pandoc-@-mode.")

(defun pandoc-quit-@-select ()
  "Leave pandoc--@-select-buffer without selecting an (@)-label."
  (interactive)
  (remove-overlays)
  (set-window-configuration pandoc--window-config)
  (switch-to-buffer pandoc--pre-select-buffer))

(defun pandoc-next-@ ()
  "Highlight next (@)-definition."
  (interactive)
  (if (= (count-lines (point) (point-max)) 2)
      (beep)
    (forward-line 2)
    (move-overlay pandoc--@-overlay (point) (point-at-eol))))

(defun pandoc-prev-@ ()
  "Highlight previous (@)-definition."
  (interactive)
  (if (= (point) (point-min))
      (beep)
    (forward-line -2)
    (move-overlay pandoc--@-overlay (point) (point-at-eol))))

(defun pandoc-goto-first-@ ()
  "Highlight the first (@)-definition."
  (interactive)
  (goto-char (point-min))
  (move-overlay pandoc--@-overlay (point) (point-at-eol)))

(defun pandoc-goto-last-@ ()
  "Highlight the last (@)-definition."
  (interactive)
  (goto-char (point-max))
  (forward-line -2)
  (move-overlay pandoc--@-overlay (point) (point-at-eol)))

(defun pandoc-select-current-@ ()
  "Leave pandoc--@-select-buffer and insert selected (@)-label at point."
  (interactive)
  (looking-at " \\((@.*?)\\)")
  (let ((label (match-string 1)))
    (remove-overlays)
    (set-window-configuration pandoc--window-config)
    (switch-to-buffer pandoc--pre-select-buffer)
    (insert label)))

(define-derived-mode pandoc-@-mode
  fundamental-mode "Pandoc-select"
  "Major mode for the Pandoc-select buffer."
  (setq buffer-read-only t)
  (setq truncate-lines t))

(defvar pandoc-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map "\C-c/" #'pandoc-main-hydra/body)
    map)
  "Keymap for pandoc-mode.")

;;;###autoload
(define-minor-mode pandoc-mode
  "Minor mode for interacting with Pandoc."
  :init-value nil :lighter (:eval (concat " Pandoc/" (pandoc--get 'write))) :global nil
  (cond
   (pandoc-mode    ; pandoc-mode is turned on
    (setq pandoc--local-settings (copy-tree pandoc--options))
    (pandoc--set 'read (cdr (assq major-mode pandoc-major-modes)))
    (setq pandoc--settings-modified-flag nil)
    ;; Make sure the output buffer exists.
    (get-buffer-create pandoc--output-buffer-name)
    (pandoc-faces-load))
   ((not pandoc-mode)    ; pandoc-mode is turned off
    (setq pandoc--local-settings nil
          pandoc--settings-modified-flag nil)
    (pandoc-faces-unload))))

;;;###autoload
(defun conditionally-turn-on-pandoc ()
  "Turn on pandoc-mode if a pandoc settings file exists.
This is for use in major mode hooks."
  (when (and (buffer-file-name)
             (file-exists-p (pandoc--create-settings-filename 'local (buffer-file-name) "default")))
    (pandoc-mode 1)))

(defun pandoc-toggle-extension (extension rw)
  "Toggle the value of EXTENSION.
RW is either `read' or `write', indicating whether the extension
should be toggled for the input or the output format."
  (interactive (list (completing-read "Extension: " pandoc--extensions nil t)
                     (intern (completing-read "Read/write: " '("read" "write") nil t))))
  (let* ((current-value (pandoc--get-extension extension rw))
         (new-value (cond
                     ((memq current-value '(+ -)) ; if the value is set explicitly
                      nil)  ; we can simply return it to the default
                     ((pandoc--extension-in-format-p extension (pandoc--get rw) rw) ; if the extension is part of the current format
                      '-)  ; we explicitly unset it
                     (t '+)))) ; otherwise we explicitly set it
    (pandoc--set-extension extension rw new-value)))

(defun pandoc-toggle-read-extension-by-number (n)
  "Toggle a `read' extension.
N is the index of the extension in `pandoc--extensions'."
  (interactive "P")
  (let* ((ext (caar (nthcdr (1- n) pandoc--extensions))))
    (pandoc-toggle-extension ext 'read)))

(defun pandoc-toggle-write-extension-by-number (n)
  "Toggle a `write' extension.
N is the index of the extension in `pandoc--extensions'."
  (interactive "P")
  (let* ((ext (caar (nthcdr (1- n) pandoc--extensions))))
    (pandoc-toggle-extension ext 'write)))

(defun pandoc--create-settings-filename (type filename output-format)
  "Create a settings filename.
TYPE is the type of settings file, either 'local or 'project.
FILENAME is name of the file for which the settings file is to be
created, OUTPUT-FORMAT the output format of the settings file,
which is recorded in its name.  The return value is an absolute
filename."
  (setq filename (expand-file-name filename))
  (cond
   ((eq type 'local)
    (concat (file-name-directory filename) "." (file-name-nondirectory filename) "." output-format ".pandoc"))
   ((eq type 'project)
    (concat (file-name-directory filename) "Project." output-format ".pandoc"))))

(defun pandoc--create-global-settings-filename (format)
  "Create a global settings filename.
FORMAT is the output format to use."
  (concat (file-name-as-directory pandoc-data-dir) format ".pandoc"))

(defun pandoc--format-all-options (input-file &optional pdf)
  "Create a list of strings with pandoc options for the current buffer.
INPUT-FILE is the name of the input file.  If PDF is non-nil, an
output file is always set, which gets the suffix `.pdf'.  If the
output format is \"odt\", \"epub\" or \"docx\" but no output file
is specified, one will be created."
  (let ((read (format "--read=%s%s%s" (pandoc--get 'read) (if (pandoc--get 'read-lhs) "+lhs" "")
                      (pandoc--format-extensions (pandoc--get 'read-extensions))))
        (write (if pdf
                   (if (member (pandoc--get 'write) pandoc--pdf-able-formats)
                       (format "--write=%s" (pandoc--get 'write))
                     "--write=latex")
                 (format "--write=%s%s%s" (pandoc--get 'write) (if (pandoc--get 'write-lhs) "+lhs" "")
                         (pandoc--format-extensions (pandoc--get 'write-extensions)))))
        (output (pandoc--format-output-option input-file pdf))
        (list-options (mapcar (lambda (option)
                                (pandoc--format-list-options option (pandoc--get option)))
                              pandoc--list-options))
        (alist-options (mapcar (lambda (option)
                                 (pandoc--format-alist-options option (pandoc--get option)))
                               pandoc--alist-options))
        (cli-options (pandoc--format-cli-options)))
    ;; Note: list-options and alist-options are both lists of lists, so we need to flatten them first.
    (delq nil (append (list read write output) cli-options (apply #'append list-options) (apply #'append alist-options)))))

(defun pandoc--format-extensions (extensions)
  "Create a string of extensions to be added to the Pandoc command line.
EXTENSIONS is an alist of (<extension> . <value>) pairs."
  (mapconcat (lambda (elt)
               (if (cdr elt)
                   (format "%s%s" (cdr elt) (car elt))
                 ""))
             extensions
             ""))

(defun pandoc--format-output-option (input-file pdf)
  "Create the output option for calling Pandoc.
INPUT-FILE is the name of the input file.  PDF is t if the output
file is a pdf file.  Return a string that can be added to the
call to Pandoc."
  (cond
   ((or (eq (pandoc--get 'output) t) ; if the user set the output file to T
        (and (null (pandoc--get 'output)) ; or if the user set no output file but either
             (or pdf                    ; (i) we're converting to pdf, or
                 (member (pandoc--get 'write) ; (ii) the output format is odt, epub or docx
                         '("odt" "epub" "docx")))))
    (format "--output=%s/%s%s"          ; we create an output file name.
            (expand-file-name (or (pandoc--get 'output-dir)
                                  (file-name-directory input-file)))
            (file-name-sans-extension (file-name-nondirectory input-file))
            (if pdf
                ".pdf"
              (cadr (assoc (pandoc--get 'write) pandoc-output-format-extensions)))))
   ((stringp (pandoc--get 'output)) ; if the user set an output file,
    (format "--output=%s/%s"      ; we combine it with the output directory
            (expand-file-name (or (pandoc--get 'output-dir)
                                  (file-name-directory input-file)))
            (if pdf                  ; and check if we're converting to pdf
                (concat (file-name-sans-extension (pandoc--get 'output)) ".pdf")
              (pandoc--get 'output))))
   (t nil)))

(defun pandoc--format-list-options (option values)
  "Create a list of cli options for OPTION from the values in VALUES."
  (mapcar (lambda (value)
            (format "--%s=%s" option (if (eq (get option 'pandoc-list-type) 'file)
                                         (pandoc--expand-absolute-path value)
                                       value)))
          values))

(defun pandoc--format-alist-options (option alist)
  "Create a list of cli options for OPTION from the key-value pairs in ALIST."
  (mapcar (lambda (kv)
            (let ((key (car kv))
                  (value (cdr kv)))
              ;; if key or value contains a colon, we use the short form
              ;; of the option, because it uses = to separate the two.
              (if (or (string-match-p ":" key)
                      (string-match-p ":" value))
                  ;; the only two alist options are `variable' and
                  ;; `metadata', whose short forms are `V' and `M',
                  ;; respectively, so we can just capitalise their first
                  ;; letters.
                  (format "-%c %s%s" (upcase (aref (symbol-name option) 0))
                          key
                          (if (eq value t)
                              ""
                            (format "=%s" value)))
                (format "--%s=%s%s" option key
                        (if (eq value t)
                            ""
                          (format ":%s" value))))))
          alist))

(defun pandoc--format-cli-options ()
  "Create a list of options in `pandoc--cli-options'."
  (mapcar (lambda (option)
            (let ((value (pandoc--get option)))
              (when (and value
                         (memq option pandoc--filepath-options))
                (setq value (pandoc--expand-absolute-path value)))
              (cond
               ((eq value t) (format "--%s" option))
               ((or (numberp value)
                    (stringp value)) (format "--%s=%s" option value))
               (t nil))))
          pandoc--cli-options))

(defun pandoc-process-directives (output-format)
  "Processes pandoc-mode @@-directives in the current buffer.
OUTPUT-FORMAT is passed unchanged to the functions associated
with the @@-directives."
  (interactive (list (pandoc--get 'write)))
  (mapc #'funcall pandoc-directives-hook)
  (let ((case-fold-search nil)
        (directives-regexp (concat "\\([\\]?\\)@@" (regexp-opt (mapcar #'car pandoc-directives) t))))
    (goto-char (point-min))
    (while (re-search-forward directives-regexp nil t)
      (if (string= (match-string 1) "\\")
          (delete-region (match-beginning 1) (match-end 1))
        (let ((@@-beg (match-beginning 0))
              (@@-end (match-end 0))
              (directive-fn (cdr (assoc (match-string 2) pandoc-directives))))
          (cond
           ((eq (char-after) ?{) ; if there is an argument.
            ;; note: point is on the left brace, and scan-lists
            ;; returns the position *after* the right brace. we need
            ;; to adjust both values to get the actual argument.
            (let* ((arg-beg (1+ (point)))
                   (arg-end (1- (scan-lists (point) 1 0)))
                   (text (buffer-substring-no-properties arg-beg arg-end)))
              (goto-char @@-beg)
              (delete-region @@-beg (1+ arg-end))
              (insert (funcall directive-fn output-format text)))
            (goto-char @@-beg))
           ;; check if the next character is not a letter or number.
           ;; if it is, we're actually on a different directive.
           ((looking-at "[a-zA-Z0-9]") t)
           ;; otherwise there is no argument.
           (t (goto-char @@-beg)
              (delete-region @@-beg @@-end) ; else there is no argument
              (insert (funcall directive-fn output-format))
              (goto-char @@-beg))))))))

(defun pandoc--process-lisp-directive (_ lisp)
  "Process @@lisp directives.
The first argument is the output argument and is ignored.  LISP
is the argument of the @@lisp directive."
  (format "%s" (eval (car (read-from-string lisp)))))

(defun pandoc--process-include-directive (_ include-file)
  "Process @@include directives.
The first argument is the output argument and is ignored.
INCLUDE-FILE is the argument of the @@include directive."
  (with-temp-buffer
    (insert-file-contents include-file)
    (buffer-string)))

(defun pandoc--get-file-local-options (buffers)
  "Return all pandoc related file-local variables and their values.
These are file local variables beginning with `pandoc/'.  Return
value is an alist of (var . value) pairs.  The values are
searched in BUFFERS, which is a list of buffers.  The first value
found for a particular value is the one returned.  In other
words, a value from a buffer earlier in BUFFERS overrides the
value of a later buffer."
  (delq nil (mapcar (lambda (option)
                      (let ((var (intern (concat "pandoc/" (symbol-name (car option)))))
                            (bs buffers))
                        (while (and bs (not (local-variable-p var (car bs))))
                          (setq bs (cdr bs)))
                        (when bs
                          (cons var (buffer-local-value var (car bs))))))
                    pandoc--options)))

;; `pandoc-call-external' sets up a process sentinel that needs to refer to
;; `pandoc-binary' to provide an informative message. We want to allow a
;; buffer-local value of `pandoc-binary', but the process sentinel doesn't
;; have the necessary context. With `lexical-binding' set to t, we could
;; make the sentinel a closure, but this only works for Emacs >= 24.1. An
;; alternative way is to use a global variable, which, however, means that
;; we can only have one pandoc subprocess at a time. Hopefully that won't
;; be a problem.

(defvar pandoc--local-binary "pandoc"
  "Temporary store for the buffer-local value of `pandoc-binary'.")

(defun pandoc--call-external (output-format &optional pdf region)
  "Call pandoc on the current buffer.
This function creates a temporary buffer and sets up the required
local options.  The contents of the current buffer is copied into
the temporary buffer, the @@-directives are processed, after
which pandoc is called.

OUTPUT-FORMAT is the format to use.  If t, the current buffer's
output format is used.  If PDF is non-nil, a pdf file is created.
REGION is a cons cell specifying the beginning and end of the
region to be sent to pandoc.

If the current buffer's \"master file\" option is set, that file
is processed instead.  The output format is taken from the current
buffer, however, unless one is provided specifically.  REGION is
also ignored in this case."
  (let* ((orig-buffer (current-buffer))
         (buffer (if (pandoc--get 'master-file)
                     (find-file-noselect (pandoc--get 'master-file))
                   (current-buffer)))
         (filename (buffer-file-name buffer))
         (display-name (buffer-name)))
    ;; If the buffer is visiting a file, we want to display the file name in
    ;; messages. If the buffer is not visiting a file, we create a file name in
    ;; case we need one, but we display the buffer name in messages.
    (if filename
        (setq display-name (file-name-nondirectory filename))
      (setq filename (concat "./" (cl-remove-if-not (lambda (c)
                                                      (string-match-p "[[:alpha:][:digit:]+_.-]" (char-to-string c)))
                                                    (buffer-name)))))
    ;; if there's a master file, ignore the region
    (if (pandoc--get 'master-file)
        (setq region nil))
    ;; keep track of the buffer-local value of `pandoc-binary', if there is one
    (setq pandoc--local-binary (buffer-local-value 'pandoc-binary buffer))
    (with-current-buffer buffer
      ;; we use with-current-buffer so that we can work on the master file
      ;; if there is one. we then change to a temp buffer, so we can
      ;; process @@-directives without having to undo them and set the
      ;; options independently of the original buffer.
      (with-temp-buffer
        (cond
         ;; if an output format was provided, try and load a settings file for it
         ((stringp output-format)
          (unless (and filename
                       (pandoc--load-settings-for-file (expand-file-name filename) output-format t))
            ;; if no settings file was found, unset all options except input and output format
            (setq pandoc--local-settings (copy-tree pandoc--options))
            (pandoc--set 'write output-format)
            (pandoc--set 'read (pandoc--get 'read buffer))))
         ;; if no output format was provided, we use BUFFER's options,
         ;; except the output format, which we take from ORIG-BUFFER:
         ((eq output-format t)
          (setq pandoc--local-settings (buffer-local-value 'pandoc--local-settings buffer))
          (pandoc--set 'write (pandoc--get 'write orig-buffer))))
        ;; copy any local `pandoc/' variables from `orig-buffer' or
        ;; `buffer' (the values in `orig-buffer' take precedence):
        (dolist (option (pandoc--get-file-local-options (list orig-buffer buffer)))
          (set (make-local-variable (car option)) (cdr option)))
        (let ((option-list (pandoc--format-all-options filename pdf)))
          (insert-buffer-substring-no-properties buffer (car region) (cdr region))
          (insert "\n") ; Insert a new line. If Pandoc does not encounter a newline on a single line, it'll hang forever.
          (message "Running %s on %s" (file-name-nondirectory pandoc--local-binary) display-name)
          (pandoc-process-directives (pandoc--get 'write))
          (with-current-buffer (get-buffer-create pandoc--output-buffer-name)
            (erase-buffer))
          (pandoc--log 'log "%s\n%s" (make-string 50 ?=) (current-time-string))
          (pandoc--log 'log "Calling %s with:\n\n%s %s" (file-name-nondirectory pandoc--local-binary) pandoc--local-binary (mapconcat #'identity option-list " "))
	  (let ((coding-system-for-read 'utf-8)
                (coding-system-for-write 'utf-8)
                (log-success (lambda (file binary)
                               (pandoc--log 'message "%s: %s finished successfully"
                                      (file-name-nondirectory file)
                                      (file-name-nondirectory binary))))
                (log-failure (lambda (file binary)
                               (pandoc--log 'message "%s: Error in %s process"
                                      (file-name-nondirectory file)
                                      (file-name-nondirectory binary)))))
            (cond
             (pandoc-use-async
              (let* ((process-connection-type pandoc-process-connection-type)
                     (process (apply #'start-process "pandoc-process" (get-buffer-create pandoc--output-buffer-name) pandoc--local-binary option-list)))
                (set-process-sentinel process (lambda (_ e)
                                                (cond
                                                 ((string-equal e "finished\n")
                                                  (funcall log-success display-name pandoc--local-binary)
                                                  (run-hooks 'pandoc-async-success-hook))
                                                 (t (funcall log-failure display-name pandoc--local-binary)
                                                    (display-buffer pandoc--output-buffer-name)))))
                (process-send-region process (point-min) (point-max))
                (process-send-eof process)))
             ((not pandoc-use-async)
              (if (= 0 (apply #'call-process-region (point-min) (point-max) pandoc--local-binary nil (get-buffer-create pandoc--output-buffer-name) t option-list))
                  (funcall log-success display-name pandoc--local-binary)
                (funcall log-failure display-name pandoc--local-binary)
                (display-buffer pandoc--output-buffer-name))))))))))

(defun pandoc-run-pandoc (&optional prefix)
  "Run pandoc on the current document.
If called with a PREFIX argument, the user is asked for an output
format.  Otherwise, the output format currently set in the buffer
is used.

If the region is active, pandoc is run on the region instead of
the buffer."
  (interactive "P")
  (pandoc--call-external (if prefix
                       (completing-read "Output format to use: "
                                        (pandoc--extract-formats 'output)
                                        nil t)
                     t)
                   nil
                   (if (use-region-p)
                       (cons (region-beginning) (region-end)))))

(defvar-local pandoc--output-format-for-pdf nil
  "Output format used to for pdf conversion.
  Set the first time the user converts to pdf.  Unset when the
user changes output format.")

(defun pandoc-convert-to-pdf (&optional prefix)
  "Convert the current document to pdf.
If the output format of the current buffer can be used to create
a pdf (latex, context, or html5), the buffer's options are used.
If not, the user is asked to supply a format.  If a settings file
for the user-supplied format exists, the settings from this file
are used for conversion.  If no such settings file exists, only
the input and output format are set, all other options are unset.
This user-supplied output format is persistent: the next pdf
conversion uses the same format.

If called with a PREFIX argument \\[universal-argument], always ask the user for a
pdf-able format.

Note that if the user changes the output format for the buffer,
the format for pdf conversion is unset.

If the region is active, pandoc is run on the region instead of
the buffer (except when a master file is set, in which case
pandoc is always run on the master file)."
  ;; TODO When the region is active, it might be nice to run pandoc on the
  ;; region but use the master file's settings.
  (interactive "P")
  (let ((ask (and (listp prefix) (eq (car prefix) 4))))
    (cond
     ((and (not ask)
           (member (pandoc--get 'write) pandoc--pdf-able-formats))
      (setq pandoc--output-format-for-pdf t)) ; Use buffer's output format and settings.
     ((or ask
          (not pandoc--output-format-for-pdf))
      (setq pandoc--output-format-for-pdf (completing-read "Specify output format for pdf creation: " pandoc--pdf-able-formats nil t nil nil (car pandoc--pdf-able-formats))))))
  (pandoc--call-external pandoc--output-format-for-pdf t (when (use-region-p) (cons (region-beginning) (region-end)))))

(defun pandoc-set-default-format ()
  "Set the current output format as default.
This is done by creating a symbolic link to the relevant settings
files.  (Therefore, this function is not available on Windows.)"
  (interactive)
  (if (eq system-type 'windows-nt)
      (message "This option is not available on MS Windows")
    (let ((current-settings-file
           (file-name-nondirectory (pandoc--create-settings-filename 'local (buffer-file-name)
                                                               (pandoc--get 'write))))
          (current-project-file
           (file-name-nondirectory (pandoc--create-settings-filename 'project (buffer-file-name)
                                                               (pandoc--get 'write)))))
      (when (not (file-exists-p current-settings-file))
        (pandoc--save-settings 'local (pandoc--get 'write)))
      (make-symbolic-link current-settings-file
                          (pandoc--create-settings-filename 'local (buffer-file-name) "default") t)
      (when (file-exists-p current-project-file)
        (make-symbolic-link current-project-file
                            (pandoc--create-settings-filename 'project (buffer-file-name) "default") t))
      (message "`%s' set as default output format." (pandoc--get 'write)))))

(defun pandoc-save-settings-file ()
  "Save the settings of the current buffer.
This function just calls pandoc--save-settings with the
appropriate output format."
  (interactive)
  (pandoc--save-settings 'local (pandoc--get 'write)))

(defun pandoc-save-project-file ()
  "Save the current settings as a project file."
  (interactive)
  (pandoc--save-settings 'project (pandoc--get 'write)))

(defun pandoc-save-global-settings-file ()
  "Save the current settings to a global settings file."
  (interactive)
  (unless (file-directory-p pandoc-data-dir)
    (make-directory pandoc-data-dir))
  (pandoc--save-settings 'global (pandoc--get 'write)))

(defun pandoc--save-settings (type format &optional no-confirm)
  "Save the settings of the current buffer.
TYPE must be a quoted symbol and specifies the type of settings
file.  It can be `local', `project', or `global'.  FORMAT is the
output format for which the settings are to be saved.  If
NO-CONFIRM is non-nil, any existing settings file is overwritten
without asking."
  (let* ((filename (buffer-file-name))
         (settings pandoc--local-settings)
         (settings-file (if (eq type 'global)
                            (pandoc--create-global-settings-filename format)
                          (pandoc--create-settings-filename type filename format))))
    (if (and (not no-confirm)
             (file-exists-p settings-file)
             (not (y-or-n-p (format "%s file `%s' already exists.  Overwrite? "
                                    (capitalize (symbol-name type))
                                    (file-name-nondirectory settings-file)))))
        (message "%s file not written." (capitalize (symbol-name type)))
      (with-temp-buffer
        (let ((print-length nil)
              (print-level nil)
              (print-circle nil))
          (insert ";; -*- mode: emacs-lisp -*-\n\n"
                  (format ";; pandoc-mode %s settings file%s\n"
                          type
                          (if (eq type 'local)
                              (concat " for " (file-name-nondirectory filename))
                            ""))
                  (format ";; saved on %s\n\n" (format-time-string "%Y.%m.%d %H:%M")))
          (pp settings (current-buffer)))
        (let ((make-backup-files nil))
          (write-region (point-min) (point-max) settings-file))
        (message "%s settings file written to `%s'." (capitalize (symbol-name type)) (file-name-nondirectory settings-file)))
      (setq pandoc--settings-modified-flag nil))))

(defun pandoc-revert-settings ()
  "Revert settings for the current buffer.
The settings file is reread from disk, so that any changes made
to the settings that have not been saved are reverted."
  (interactive)
  (let ((format (pandoc--get 'write)))
    (setq pandoc--local-settings (copy-tree pandoc--options))
    (pandoc--load-settings-profile format 'no-confirm)))

(defun pandoc-load-default-settings ()
  "Load the default settings of the file in the current buffer.
This function is for use in `pandoc-mode-hook'."
  (pandoc--load-settings-profile "default"))

(defun pandoc--load-settings-profile (format &optional no-confirm)
  "Load the options for FORMAT from the corresponding settings file.
If NO-CONFIRM is t, no confirmation is asked if the current
settings have not been saved."
  (pandoc--load-settings-for-file (when (buffer-file-name)
                              (expand-file-name (buffer-file-name)))
                            format
                            no-confirm))

(defun pandoc--load-settings-for-file (file format &optional no-confirm)
  "Load the settings file of FILE for FORMAT.
Search for a local, a project and a global settings file, in that
order, and load the first one that exists and is readable.

If NO-CONFIRM is t, no confirmation is asked if the current
settings have not been saved.  FILE must be an absolute path
name.  If FILE is nil, a global settings file is read, if any.
The settings are stored in the current buffer's
`pandoc--local-settings'.  Return nil if no settings or project
file is found for FILE, otherwise non-nil."
  (when (and (not no-confirm)
             pandoc--settings-modified-flag
             (y-or-n-p (format "Current settings for format \"%s\" modified.  Save first? " (pandoc--get 'write))))
    (pandoc--save-settings 'local (pandoc--get 'write) t))
  (let (settings)
    ;; first try to read local settings
    (when file
      (setq settings (cons 'local (pandoc--read-settings-from-file (pandoc--create-settings-filename 'local file format)))))
    ;; if it fails, try project settings
    (when (and file (not (cdr settings)))
      (setq settings (cons 'project (pandoc--read-settings-from-file (pandoc--create-settings-filename 'project file format)))))
    ;; if that fails too, or if there is no file, try reading global settings
    (unless (cdr settings)
      (setq settings (cons 'global (pandoc--read-settings-from-file (pandoc--create-global-settings-filename format)))))
    ;; now set them
    (when (cdr settings)
      (setq pandoc--local-settings (cdr settings))
      (message "%s settings file loaded for format \"%s\"." (capitalize (symbol-name (car settings))) format))))

(defun pandoc--read-settings-from-file (file)
  "Read the settings in FILE and return them.
If FILE does not exist or cannot be read, return nil."
  (if (file-readable-p file)
      (with-temp-buffer
        (insert-file-contents file)
        (goto-char (point-min))
        (if (looking-at "#") ; We're probably dealing with an old settings file.
            (pandoc--read-old-settings-from-buffer)
          (let ((flist (when (search-forward "(" nil t)
                         (forward-char -1)
                         (read (current-buffer)))))
            (if (listp flist)
                flist))))))

(defun pandoc--read-old-settings-from-buffer ()
  "Read old-style settings from the current buffer.
`pandoc--settings-modified-flag' is set, so that the user will be
asked to save the settings on exit.  Return an alist with the
options and their values."
  (goto-char (point-min))
  (let (options)                        ; we collect the options in a list
    (while (re-search-forward "^\\([a-z-]*\\)::\\(.*?\\)$" nil t)
      (let ((option (intern (match-string 1)))
            (value (match-string 2)))
        ;; If the option is a variable or extension, we read its name and
        ;; value and add them to the alist as a dotted list.
        (push (if (memq option '(variable read-extensions write-extensions))
                  (progn
                    (string-match "^\\(.*?\\):\\(.*?\\)$" value)
                    (cons option (cons (match-string 1 value)
                                       (if (eq option 'variable)
                                           (match-string 2 value)
                                         (intern (match-string 2 value))))))
                (cons option (cond
                              ((string-match "^[0-9]$" value) (string-to-number value))
                              ((string= "t" value) t)
                              ((string= "nil" value) nil)
                              (t value))))
              options)))
    ;; `options' isn't in the proper format for pandoc--local-settings yet:
    ;; there may be multiple variables and extensions in it. Since we're in
    ;; a temp buffer, we can simply use pandoc--set to set all options and
    ;; then return the local value of `pandoc--local-settings'.
    (setq pandoc--local-settings (copy-tree pandoc--options))
    (mapc (lambda (option)
            (pandoc--set (car option) (cdr option)))
          options)
    pandoc--local-settings))

(defun pandoc-view-output ()
  "Displays the *Pandoc output* buffer."
  (interactive)
  (display-buffer pandoc--output-buffer-name))

(defun pandoc-view-settings ()
  "Displays the settings file in a *Help* buffer."
  (interactive)
  ;; remove all options that do not have a value.
  (let* ((remove-defaults (lambda (alist)
                            (delq nil (mapcar (lambda (option)
                                                (if (cdr option)
                                                    option))
                                              alist))))
         (settings (copy-tree pandoc--local-settings))
         (read-extensions (assq 'read-extensions settings))
         (write-extensions (assq 'write-extensions settings))
         (buffers (list (current-buffer)
                        (if (pandoc--get 'master-file)
                            (find-file-noselect (pandoc--get 'master-file)))))
         (file-locals (pandoc--get-file-local-options buffers)))
    (when read-extensions
      (setcdr read-extensions (funcall remove-defaults (cdr read-extensions))))
    (when write-extensions
      (setcdr write-extensions (funcall remove-defaults (cdr write-extensions))))
    (setq settings (funcall remove-defaults settings))
    (with-help-window " *Pandoc Help*"
      (let ((print-length nil)
            (print-level nil)
            (print-circle nil))
        (princ "Current settings:\n\n")
        (pp settings)
        (when file-locals
          (princ "\n\nFile-local settings:\n\n")
          (pp file-locals))))))

(defun pandoc-view-log ()
  "Display the log buffer in a temporary window."
  (interactive)
  (display-buffer (get-buffer-create pandoc--log-buffer-name)))

(defun pandoc-insert-@ ()
  "Insert a new labeled (@) list marker at point."
  (interactive)
  (let ((label (pandoc--@-counter-inc)))
    (insert (format "(@%s)" label))))

(defun pandoc--collect-@-definitions ()
  "Collect (@)-definitions and return them as a list."
  (save-excursion
    (goto-char (point-min))
    (let (definitions)
      (while (re-search-forward "^[[:space:]]*\\((@.*?).*\\)$" nil t)
        (push (match-string-no-properties 1) definitions))
      (nreverse definitions))))

(defun pandoc-select-@ ()
  "Show a list of (@)-definitions and allow the user to choose one."
  (interactive)
  (let ((definitions (pandoc--collect-@-definitions)))
    (setq pandoc--window-config (current-window-configuration))
    (setq pandoc--pre-select-buffer (current-buffer))
    (setq pandoc--@-buffer (get-buffer-create " *Pandoc select*"))
    (set-buffer pandoc--@-buffer)
    (pandoc-@-mode)
    (let ((buffer-read-only nil))
      (erase-buffer)
      (mapc (lambda (definition)
              (insert (concat " " definition "\n\n")))
            definitions)
      (goto-char (point-min))
      (setq pandoc--@-overlay (make-overlay (point-min) (point-at-eol)))
      (overlay-put pandoc--@-overlay 'face 'highlight))
    (select-window (display-buffer pandoc--@-buffer))))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Functions to set specific options. ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(defun pandoc-set-write (format)
  "Set the output format to FORMAT.
If a settings and/or project file exists for FORMAT, they are
loaded.  If none exists, all options are unset (except the input
format)."
  (interactive (list (completing-read "Set output format to: "
                                      (pandoc--extract-formats 'output)
                                      nil t)))
  (when (and pandoc--settings-modified-flag
             (y-or-n-p (format "Current settings for output format \"%s\" changed.  Save? " (pandoc--get 'write))))
    (pandoc--save-settings 'local (pandoc--get 'write) t))
  (unless (pandoc--load-settings-profile format t)
    (setq pandoc--local-settings (copy-tree pandoc--options))
    (pandoc--set 'write format)
    (pandoc--set 'read (cdr (assq major-mode pandoc-major-modes))))
  (setq pandoc--settings-modified-flag nil)
  (setq pandoc--output-format-for-pdf nil)
  (message "Output format set to `%s'" format))

(defun pandoc-set-read (format)
  "Set the input format to FORMAT."
  (interactive (list (completing-read "Set input format to: "
                                      (pandoc--extract-formats 'input)
                                      nil t)))
  (pandoc--set 'read format)
  (message "Input format set to `%s'" format))

(defun pandoc-set-output (prefix)
  "Set the output file.
If called with the PREFIX argument `\\[universal-argument] -' (or
`\\[negative-argument]', the output file is unset.  If called
with any other prefix argument, the output file is created on the
basis of the input file and the output format."
  (interactive "P")
  (pandoc--set 'output
         (cond
          ((eq prefix '-) nil)
          ((null prefix) (file-name-nondirectory (read-file-name "Output file: ")))
          (t t))))

(defun pandoc-set-data-dir (prefix)
  "Set the option `Data Directory'.
If called with the PREFIX argument `\\[universal-argument] -' (or
`\\[negative-argument]'), the data directory is set to NIL, which
means use $HOME/.pandoc."
  (interactive "P")
  (pandoc--set 'data-dir
         (if (eq prefix '-)
             nil
           (read-directory-name "Data directory: " nil nil t))))

(defun pandoc-set-output-dir (prefix)
  "Set the option `Output Directory'.
If called with the PREFIX argument `\\[universal-argument] -' (or
`\\[negative-argument]'), the output directory is set to NIL,
which means use the directory of the input file."
  (interactive "P")
  (pandoc--set 'output-dir
         (if (eq prefix '-)
             nil
           (read-directory-name "Output directory: " nil nil t))))

(defun pandoc-set-extract-media (prefix)
  "Set the option `Extract media'.
If called with the PREFIX argument `\\[universal-argument] -' (or
`\\[negative-argument]'), no media files are extracted."
  (interactive "P")
  (pandoc--set 'extract-media
         (if (eq prefix '-)
             nil
           (read-directory-name "Extract media files to directory: " nil nil t))))

(defun pandoc-set-file-scope (prefix)
  "Set the option `File scope'.
If called with the PREFIX argument `\\[universal-argument] -' (or
`\\[negative-argument]'), document scope is used."
  (interactive "P")
  (pandoc--set 'file-scope (if (eq prefix '-) nil t)))

(defun pandoc-set-master-file (prefix)
  "Set the master file.
If called with the PREFIX argument `\\[universal-argument] -' (or
`\\[negative-argument]'), the master file is set to nil, which
means the current file is the master file."
  (interactive "P")
  (pandoc--set 'master-file (cond
                       ((eq prefix '-) nil)
                       (t (pandoc--read-file-name "Master file: " default-directory (not prefix))))))

(defun pandoc-set-this-file-as-master ()
  "Set the current file as master file.
This option creates a Project settings file in the current
directory to ensure that all files use the current file as master
file."
  (interactive)
  (pandoc--set 'master-file (buffer-file-name))
  (pandoc--save-settings 'project (pandoc--get 'write)))

(defun pandoc-toggle-interactive (prefix)
  "Toggle one of pandoc's binary options.
If called with the PREFIX argument `\\[universal-argument] -' (or
`\\[negative-argument]'), the options is unset.  If called with
any other prefix argument, the option is set.  Without any prefix
argument, the option is toggled."
  (interactive "P")
  (let* ((completion-ignore-case t)
         (option (cdr (assoc (completing-read (format "%s option: " (cond
                                                                     ((eq prefix '-) "Unset")
                                                                     ((null prefix) "Toggle")
                                                                     (t "Set")))
                                              pandoc--switches nil t) pandoc--switches))))
    (pandoc--set option (cond
                   ((eq prefix '-) nil)
                   ((null prefix) (not (pandoc--get option)))
                   (t t)))
    (message "Option `%s' %s." (car (rassq option pandoc--switches)) (if (pandoc--get option)
                                                                   "set"
                                                                 "unset"))))

(easy-menu-define pandoc-mode-menu pandoc-mode-map "Pandoc menu"
  `("Pandoc"
    ["Run Pandoc" pandoc-run-pandoc :active t]
    ["Create PDF" pandoc-convert-to-pdf :active t]
    ["View Output Buffer" pandoc-view-output :active t]
    ["View Log Buffer" pandoc-view-log :active t]
    ("Settings Files"
     ["Save File Settings" pandoc-save-settings-file :active t]
     ["Save Project File" pandoc-save-project-file :active t]
     ["Save Global Settings File" pandoc-save-global-settings-file :active t]
     ["Revert Settings" pandoc-revert-settings :active t]
     ["Set As Default Format" pandoc-set-default-format :active (not (eq system-type 'windows-nt))])
    ("Example Lists"
     ["Insert New Example" pandoc-insert-@ :active t]
     ["Select And Insert Example Label" pandoc-select-@ :active t])
    "--"
    ["View Current Settings" pandoc-view-settings :active t]

    ,(append (cons "Input Format"
                   (mapcar (lambda (option)
                             (vector (car option)
                                     `(pandoc--set 'read ,(cdr option))
                                     :active t
                                     :style 'radio
                                     :selected `(string= (pandoc--get 'read)
                                                         ,(cdr option))))
                           pandoc--input-formats-menu))
             (list ["Literal Haskell" (pandoc--toggle 'read-lhs)
                    :active (member (pandoc--get 'read) '("markdown" "rst" "latex"))
                    :style toggle :selected (pandoc--get 'read-lhs)])
             (list (append (list "Extensions" :visible `(string-match "markdown" (pandoc--get 'read)))
                           (mapcar (lambda (ext)
                                     (vector (car ext)
                                             `(pandoc-toggle-extension ,(car ext) 'read)
                                             :active t
                                             :style 'toggle
                                             :selected `(pandoc--extension-active-p ,(car ext) 'read)))
                                   pandoc--extensions))))

    ,(append (cons "Output Format"
                   (mapcar (lambda (option)
                             (vector (cadr option)
                                     `(pandoc-set-write ,(car option))
                                     :active t
                                     :style 'radio
                                     :selected `(string= (pandoc--get 'write)
                                                         ,(car option))))
                           (pandoc--extract-formats 'output)))
             (list ["Literal Haskell" (pandoc--toggle 'write-lhs)
                    :active (member (pandoc--get 'write)
                                    '("markdown" "rst" "latex" "beamer" "html" "html5"))
                    :style toggle :selected (pandoc--get 'write-lhs)])
             (list (append (list "Extensions" :visible `(string-match "markdown" (pandoc--get 'write)))
                           (mapcar (lambda (ext)
                                     (vector (car ext)
                                             `(pandoc-toggle-extension ,(car ext) 'write)
                                             :active t
                                             :style 'toggle
                                             :selected `(pandoc--extension-active-p ,(car ext) 'write)))
                                   pandoc--extensions))))

    ("Files"
     ("Output File"
      ["Output To Stdout" (pandoc--set 'output nil) :active t
       :style radio :selected (null (pandoc--get 'output))]
      ["Create Output Filename" (pandoc--set 'output t) :active t
       :style radio :selected (eq (pandoc--get 'output) t)]
      ["Set Output File..." pandoc-set-output :active t
       :style radio :selected (stringp (pandoc--get 'output))])
     ("Output Directory"
      ["Use Input Directory" (pandoc--set 'output-dir nil) :active t
       :style radio :selected (null (pandoc--get 'output-dir))]
      ["Set Output Directory" pandoc-set-output-dir :active t
       :style radio :selected (pandoc--get 'output-dir)])
     ("Data Directory"
      ["Use Default Data Directory" (pandoc--set 'data-dir nil) :active t
       :style radio :selected (null (pandoc--get 'data-dir))]
      ["Set Data Directory" pandoc-set-data-dir :active t
       :style radio :selected (pandoc--get 'data-dir)])
     ,@pandoc--files-menu
     ("Extract Media"
      ["Do Not Extract Media Files" (pandoc--set 'extract-media nil) :active t
       :style radio :selected (null (pandoc--get 'extract-media))]
      ["Extract Media Files" pandoc-set-extract-media :active t
       :style radio :selected (pandoc--get 'extract-media)])
     ("Scope"
      ["Document Scope" (pandoc--set 'file-scope nil) :active t
       :style radio :selected (null (pandoc--get 'file-scope))]
      ["File Scope" pandoc-set-file-scope :active t
       :style radio :selected (pandoc--get 'file-scope)])
     ("Master File"
      ["No Master File" (pandoc-set-master-file '-) :active t :style radio :selected (null (pandoc--get 'master-file))]
      ["Use This File As Master File" pandoc-set-this-file-as-master :active t :style radio :selected (equal (pandoc--get 'master-file) (buffer-file-name))]
      ["Set Master File" pandoc-set-master-file :active t :style radio :selected (and (pandoc--get 'master-file) (not (equal (pandoc--get 'master-file) (buffer-file-name))))]))

    ("Reader Options"
     ,@pandoc--reader-menu-list)
    ("General Writer Options"
     ,@pandoc--writer-menu-list)
    ("Options For Specific Writers"
     ,@pandoc--specific-menu-list
     "--"
     ("HTML-Based Formats"
      ,@pandoc--html-menu-list)
     ("TeX-Based Formats"
      ,@pandoc--tex-menu-list)
     ("EPUB"
      ,@pandoc--epub-menu-list))
    ("Citations"
     ,@pandoc--citations-menu-list)
    ("Math Rendering"
     ,@pandoc--math-menu-list)))

;; ("Options"
;;  ,@pandoc--options-menu)
;; ("Switches"
;;  ;; put the binary options into the menu
;;  ,@(mapcar (lambda (option)
;;              (vector (car option) `(pandoc--toggle (quote ,(cdr option)))
;;                      :active t
;;                      :style 'toggle
;;                      :selected `(pandoc--get (quote ,(cdr option)))))
;;            pandoc--switches))

(easy-menu-add pandoc-mode-menu pandoc-mode-map)

;; hydras

(defhydra pandoc-main-hydra (:foreign-keys warn :exit t :hint nil)
  "
Main menu

_r_: Run Pandoc               _I_: Input format
_p_: Convert to pdf           _O_: Output format
_V_: View output buffer       _s_: Settings files
_S_: View current settings    _e_: Example lists
_L_: View log buffer
_o_: Options

"
  ("r" pandoc-run-pandoc)
  ("p" pandoc-convert-to-pdf)
  ("V" pandoc-view-output)
  ("S" pandoc-view-settings)
  ("L" pandoc-view-log)
  ("I" pandoc-input-format-hydra/body)
  ("O" pandoc-output-format-hydra/body)
  ("s" pandoc-settings-file-hydra/body)
  ("e" pandoc-@-hydra/body)
  ("o" pandoc-options-hydra/body)
  ("q" nil "Quit"))

;; Input and Output formats hydras
(let (input-formats-hydra
      output-formats-hydra)
  ;; Five helper functions take apart the description of the formats and/or the
  ;; categories as defined in `pandoc--formats' and return a docstring or a hydra
  ;; head.
  (cl-flet ((make-format-docstring ((_format descr key _mode))
                                   (format "_%s_: %s" key descr))
            (make-input-format-head ((format _descr key _mode))
                                    (list key `(pandoc-set-read ,format)))
            (make-output-format-head ((format _descr key _mode))
                                     (list key `(pandoc-set-write ,format)))
            (make-main-docstring ((_command descr key))
                                 (format "_%s_: %s" key descr))
            (make-main-head ((command _descr key))
                            (list key command)))

    ;; Define hydras for each category and collect everything needed to construct
    ;; the output format menu.
    (mapc (lambda (submenu)
            (-let [(name description key . formats) submenu]
              ;; First the input formats in this category.
              (-when-let (input-formats (--filter (memq (-last-item it) '(input both)) formats))
                (let ((input-name (concat "pandoc-input-format-" name "-hydra")))
                  (push (list (intern (concat input-name "/body")) description key) input-formats-hydra)
                  (let ((docstring (concat (--reduce-from (concat acc "\n" (make-format-docstring it))
                                                          (concat "\n" description "\n\n")
                                                          input-formats)
                                           "\n\n"))
                        (heads (--map (make-input-format-head it) input-formats)))
                    (eval `(defhydra ,(intern input-name) (:foreign-keys warn :hint nil)
                             ,docstring
                             ,@(append heads '(("q" nil "Quit") ("b" pandoc-input-format-hydra/body "Back" :exit t))))))))

              ;; Then the output formats in this category.
              (-when-let (output-formats (--filter (memq (-last-item it) '(output both)) formats))
                (let ((output-name (concat "pandoc-output-format-" name "-hydra")))
                  (push (list (intern (concat output-name "/body")) description key) output-formats-hydra)
                  (let ((docstring (concat (--reduce-from (concat acc "\n" (make-format-docstring it))
                                                          (concat "\n" description "\n\n")
                                                          output-formats)
                                           "\n\n"))
                        (heads (--map (make-output-format-head it) output-formats)))
                    (eval `(defhydra ,(intern output-name) (:foreign-keys warn :hint nil)
                             ,docstring
                             ,@(append heads '(("q" nil "Quit") ("b" pandoc-output-format-hydra/body "Back" :exit t))))))))))
          pandoc--formats)

    ;; Now create the main input and output format hydras.
    (let ((docstring (concat (--reduce-from (concat acc "\n" (make-main-docstring it))
                                            (concat "\n" "Current input format: %s(pandoc--get 'read)\n")
                                            (reverse input-formats-hydra))
                             "\n\n_X_: Extensions\n\n"))
          (heads (--map (make-main-head it) input-formats-hydra)))
      (eval `(defhydra pandoc-input-format-hydra (:foreign-keys warn :exit t :hint nil)
               ,docstring
               ,@(append heads '(("X" pandoc-read-exts-hydra/body) ("q" nil "Quit") ("b" pandoc-main-hydra/body "Back"))))))

    (let ((docstring (concat (--reduce-from (concat acc "\n" (make-main-docstring it))
                                            (concat "\n" "Current output format: %s(pandoc--get 'write)\n")
                                            (reverse output-formats-hydra))
                             "\n\n_X_: Extensions\n\n"))
          (heads (--map (make-main-head it) output-formats-hydra)))
      (eval `(defhydra pandoc-output-format-hydra (:foreign-keys warn :exit t :hint nil)
               ,docstring
               ,@(append heads '(("X" pandoc-write-exts-hydra/body) ("q" nil "Quit") ("b" pandoc-main-hydra/body "Back"))))))))

(defhydra pandoc-settings-file-hydra (:foreign-keys warn :hint nil)
  "
Settings files

_s_: Save file settings
_p_: Save project file
_g_: Save global settings file
_d_: Set current format as default
_r_: Revert settings

"
  ("s" pandoc-save-settings-file)
  ("p" pandoc-save-project-file)
  ("g" pandoc-save-global-settings-file)
  ("d" pandoc-set-default-format)
  ("r" pandoc-revert-settings)
  ("q" nil "Quit")
  ("b" pandoc-main-hydra/body "Back" :exit t))

(defhydra pandoc-@-hydra (:foreign-keys warn :exit t :hint nil)
  "
Example lists

_i_: Insert new example
_s_: Select and insert example label

"
  ("i" pandoc-insert-@)
  ("s" pandoc-select-@)
  ("q" nil "Quit")
  ("b" pandoc-main-hydra/body "Back"))

(defun pandoc--extension-active-marker (extension rw)
  "Return a marker indicating whether EXTENSION is active.
RW is either `read' or `write', indicating whether to take the
input or the output format."
  (if (pandoc--extension-active-p extension rw)
      pandoc-extension-active-marker
    pandoc-extension-inactive-marker))

(defhydra pandoc-read-exts-hydra (:foreign-keys warn :hint nil)
  (concat "\n" (pandoc--tabulate-extensions 'read) "\n\n<number> [_t_]: Toggle extension, [_q_]: Quit, [_b_]: Back")
  ("t" pandoc-toggle-read-extension-by-number)
  ("q" nil)
  ("b" pandoc-input-format-hydra/body :exit t))

(defhydra pandoc-write-exts-hydra (:foreign-keys warn :hint nil)
  (concat "\n" (pandoc--tabulate-extensions 'write) "\n\n<number> [_t_]: Toggle extension, [_q_]: Quit, [_b_]: Back")
  ("t" pandoc-toggle-write-extension-by-number)
  ("q" nil)
  ("b" pandoc-output-format-hydra/body :exit t))

(defhydra pandoc-options-hydra (:foreign-keys warn :exit t :hint nil)
  "
Options menu

_f_: Files
_r_: Reader options
_w_: General writer options
_s_: Options for specific writers
_c_: Citations
_m_: Math rendering

"
  ("f" pandoc-file-hydra/body)
  ("r" pandoc-reader-options-hydra/body)
  ("w" pandoc-writer-options-hydra/body)
  ("s" pandoc-specific-options-hydra/body)
  ("c" pandoc-citations-hydra/body)
  ("m" pandoc-math-hydra/body)
  ("q" nil "Quit")
  ("b" pandoc-main-hydra/body "Back"))

(defhydra pandoc-file-hydra (:foreign-keys warn :hint nil)
  "
File options

_o_: Output file           [%s(pandoc--pp-option 'output)]
_O_: Output directory      [%s(pandoc--pp-option 'output-dir)]
_d_: Data directory        [%s(pandoc--pp-option 'data-dir)]
_e_: Extract media files   [%s(pandoc--pp-option 'extract-media)]
_f_: File Scope            [%s(pandoc--pp-option 'file-scope)]
_m_: Master file           [%s(pandoc--pp-option 'master-file)]
_M_: Use current file as master file

"
  ("o" pandoc-set-output)
  ("O" pandoc-set-output-dir)
  ("d" pandoc-set-data-dir)
  ("e" pandoc-set-extract-media)
  ("f" pandoc-set-file-scope)
  ("m" pandoc-set-master-file)
  ("M" pandoc-set-this-file-as-master)
  ("q" nil "Quit")
  ("b" pandoc-options-hydra/body "Back" :exit t))

(define-pandoc-hydra pandoc-reader-options-hydra (:foreign-keys warn :hint nil)
  (concat "Reader options"
          "\n\n"
          (mapconcat #'car pandoc--reader-hydra-list "\n")
          "\n\n")
  (mapcar #'cdr pandoc--reader-hydra-list)
  ("q" nil "Quit")
  ("b" pandoc-options-hydra/body "Back" :exit t))

(define-pandoc-hydra pandoc-writer-options-hydra (:foreign-keys warn :hint nil)
  (concat "General writer options"
          "\n\n"
          (mapconcat #'car pandoc--writer-hydra-list "\n")
          "\n\n")
  (mapcar #'cdr pandoc--writer-hydra-list)
  ("q" nil "Quit")
  ("b" pandoc-options-hydra/body "Back" :exit t))

(define-pandoc-hydra pandoc-specific-options-hydra (:foreign-keys warn :hint nil)
  (concat "Specific writer options"
          "\n\n"
          (mapconcat #'car pandoc--specific-hydra-list "\n")
          "\n"
          (make-string 50 ?-)
          "\n"
          "_H_: HTML-based writers\n"
          "_T_: TeX-based writers\n"
          "_E_: Epub"
          "\n\n")
  (mapcar #'cdr pandoc--specific-hydra-list)
  ("H" pandoc-html-options-hydra/body :exit t)
  ("T" pandoc-tex-options-hydra/body :exit t)
  ("E" pandoc-epub-options-hydra/body :exit t)
  ("q" nil "Quit")
  ("b" pandoc-options-hydra/body "Back" :exit t))

(define-pandoc-hydra pandoc-html-options-hydra (:foreign-keys warn :hint nil)
  (concat "HTML-based writer options"
          "\n\n"
          (mapconcat #'car pandoc--html-hydra-list "\n")
          "\n\n")
  (mapcar #'cdr pandoc--html-hydra-list)
  ("q" nil "Quit")
  ("b" pandoc-specific-options-hydra/body "Back" :exit t))

(define-pandoc-hydra pandoc-tex-options-hydra (:foreign-keys warn :hint nil)
  (concat "TeX-based writer options"
          "\n\n"
          (mapconcat #'car pandoc--tex-hydra-list "\n")
          "\n\n")
  (mapcar #'cdr pandoc--tex-hydra-list)
  ("q" nil "Quit")
  ("b" pandoc-specific-options-hydra/body "Back" :exit t))

(define-pandoc-hydra pandoc-epub-options-hydra (:foreign-keys warn :hint nil)
  (concat "Epub writer options"
          "\n\n"
          (mapconcat #'car pandoc--epub-hydra-list "\n")
          "\n\n")
  (mapcar #'cdr pandoc--epub-hydra-list)
  ("q" nil "Quit")
  ("b" pandoc-specific-options-hydra/body "Back" :exit t))

(define-pandoc-hydra pandoc-citations-hydra (:foreign-keys warn :hint nil)
  (concat "Citations menu"
          "\n\n"
          (mapconcat #'car pandoc--citations-hydra-list "\n")
          "\n\n")
  (mapcar #'cdr pandoc--citations-hydra-list)
  ("q" nil "Quit")
  ("b" pandoc-options-hydra/body "Back" :exit t))

(define-pandoc-hydra pandoc-math-hydra (:foreign-keys warn :hint nil)
  (concat "Math rendering"
          "\n\n"
          (mapconcat #'car pandoc--math-hydra-list "\n")
          "\n\n")
  (mapcar #'cdr pandoc--math-hydra-list)
  ("q" nil "Quit")
  ("b" pandoc-options-hydra/body "Back" :exit t))


;;; Faces:
;;; Regexp based on github.com/vim-pandoc/vim-pandoc-syntax.
;;; Overall structure modeled after face handling in markdown-mode.el:
;;; http://jblevins.org/git/markdown-mode.git

(defvar pandoc-citation-key-face 'pandoc-citation-key-face
  "Face name to use for citations.")

(defvar pandoc-citation-marker-face 'pandoc-citation-marker-face
  "Face name to use for '@' citation identifier.")

(defvar pandoc-citation-extra-face 'pandoc-citation-extra-face
  "Face name to use for page numbers and other notation.")

(defvar pandoc-citation-brackets-face 'pandoc-citation-brackets-face
  "Face name to use for page numbers and other notation.")

(defvar pandoc-strikethrough-text-face 'pandoc-strikethrough-text-face
  "Face name to use for strikethrough text.")

(defvar pandoc-strikethrough-tilde-face 'pandoc-strikethrough-tilde-face
  "Face name to use for strikethrough delimiters.")

(defvar pandoc-directive-@@-face 'pandoc-directive-@@-face
  "Face name to use for '@@' in @@directives.")

(defvar pandoc-directive-type-face 'pandoc-directive-type-face
  "Face name to use for name of @@directives.")

(defvar pandoc-directive-braces-face 'pandoc-directive-braces-face
  "Face name to use for braces in @@directives.")

(defvar pandoc-directive-contents-face 'pandoc-directive-contents-face
  "Face name to use for contents of @@directives.")

(defface pandoc-citation-key-face
  '((t (:inherit font-lock-function-name-face)))
  "Base face for pandoc citations."
  :group 'pandoc)

(defface pandoc-citation-marker-face
  '((t (:inherit font-lock-variable-name-face)))
  "Base face for pandoc citation marker '@'."
  :group 'pandoc)

(defface pandoc-citation-extra-face
  '((t (:inherit font-lock-variable-name-face)))
  "Base face for page numbers and other pandoc citation notation."
  :group 'pandoc)

(defface pandoc-citation-brackets-face
  '((t (:inherit font-lock-function-name-face)))
  "Base face for pandoc citation brackets."
  :group 'pandoc)

(defface pandoc-strikethrough-text-face
  '((t (:strike-through t)))
  "Base face for pandoc strikethrough text."
  :group 'pandoc)

(defface pandoc-strikethrough-tilde-face
  '((t (:inherit font-lock-warning-face)))
  "Base face for pandoc strikethrough delimiters."
  :group 'pandoc)

(defface pandoc-directive-@@-face
  '((t (:inherit font-lock-type-face)))
  "Base face for pandoc-mode @@directive syntax."
  :group 'pandoc)

(defface pandoc-directive-type-face
  '((t (:inherit font-lock-preprocessor-face)))
  "Base face for pandoc-mode @@directive type (include or lisp)."
  :group 'pandoc)

(defface pandoc-directive-braces-face
  '((t (:inherit font-lock-variable-name-face)))
  "Base face for pandoc-mode @@directive braces."
  :group 'pandoc)

(defface pandoc-directive-contents-face
  '((t (:inherit font-lock-constant-face)))
  "Base face for pandoc-mode @@directive type (include or lisp)."
  :group 'pandoc)

(defconst pandoc-regex-parenthetical-citation-single
  "\\(\\[\\)\\(-?@\\)\\([-a-zA-Z0-9_+:]+\\)\\(\\]\\)"
  "Regular expression for parenthetical citations with only one key.")

(defconst pandoc-regex-parenthetical-citation-multiple
  "\\(\\[\\)\\(.*?\\)\\(-?@\\)\\([-a-zA-Z0-9_+:]+\\)\\(.*?\\)\\(\\]\\)"
  "Regular expression for parenthetical citations with page numbers or multiple keys.")

(defconst pandoc-regex-in-text-citation
  "\\[\\{0\\}\\(-?@\\)\\([-a-zA-Z0-9_+:]+\\)\\s-\\(\\[\\)\\(.*?\\)\\(\\]\\)"
  "Regular expression for stand-alone citation with anchor.")

(defconst pandoc-regex-in-text-citation-2
  "\\(?:[^[:alnum:]]\\|^\\)\\(-?@\\)\\([-a-zA-Z0-9_+:]+\\)"
  "Regular expression for stand-alone citation with no anchor.")

(defconst pandoc-regex-strikethrough
  "\\(~\\{2\\}\\)\\([^~].*?\\)\\(~\\{2\\}\\)"
  "Regular expression for pandoc markdown's strikethrough syntax.")

(defconst pandoc-regex-@@-directive
  "\\(@@\\)\\(include\\|lisp\\)\\({\\)\\(.*?\\)\\(}\\)"
  "Regular expression for pandoc-mode's @@directives.")

(defvar pandoc-faces-keywords
  (list
   (cons pandoc-regex-@@-directive
   	 '((1 pandoc-directive-@@-face)
	   (2 pandoc-directive-type-face)
	   (3 pandoc-directive-braces-face)
   	   (4 pandoc-directive-contents-face)
	   (5 pandoc-directive-braces-face)))
   (cons pandoc-regex-parenthetical-citation-single
   	 '((1 pandoc-citation-brackets-face t)
   	   (2 pandoc-citation-marker-face)
   	   (3 pandoc-citation-key-face)
   	   (4 pandoc-citation-brackets-face t)))
   (cons pandoc-regex-in-text-citation-2
   	 '((1 pandoc-citation-marker-face)
   	   (2 pandoc-citation-key-face)))
   (cons pandoc-regex-parenthetical-citation-multiple
         '((1 pandoc-citation-brackets-face t)
           (2 pandoc-citation-extra-face)
           (3 pandoc-citation-marker-face)
           (4 pandoc-citation-key-face)
           (5 pandoc-citation-extra-face append)
           (6 pandoc-citation-brackets-face t)))
   (cons pandoc-regex-in-text-citation
	 '((1 pandoc-citation-marker-face)
	   (2 pandoc-citation-key-face)
	   (3 pandoc-citation-brackets-face)
	   (4 pandoc-citation-extra-face)
	   (5 pandoc-citation-brackets-face)))
   (cons pandoc-regex-strikethrough
   	 '((1 pandoc-strikethrough-tilde-face)
   	   (2 pandoc-strikethrough-text-face )
   	   (3 pandoc-strikethrough-tilde-face))))
  "Keywords for pandoc faces.")

(defun pandoc-faces-load ()
  "Load pandoc-faces."
  (font-lock-add-keywords nil pandoc-faces-keywords)
  (if (fboundp 'font-lock-flush)
      (font-lock-flush)
    (with-no-warnings
      (font-lock-fontify-buffer))))

(defun pandoc-faces-unload ()
  "Unload pandoc-faces."
  (font-lock-remove-keywords nil pandoc-faces-keywords)
  (if (fboundp 'font-lock-flush)
      (font-lock-flush)
    (with-no-warnings
      (font-lock-fontify-buffer))))

;;; Citation jumping:
;;; Jump to citation in a bibliography file.

(defun pandoc-jump-to-reference ()
  "Display the BibTeX reference for the citation key at point.
Extract the key at point and pass it to the function in
`pandoc-citation-jump-function', together with a list of the
current buffer's BibTeX files."
  (interactive)
  (let ((biblist (pandoc--get 'bibliography)))
    (if biblist
        (cond
         ((thing-at-point-looking-at pandoc-regex-in-text-citation)
          (funcall pandoc-citation-jump-function (match-string-no-properties 4) biblist))
         ((thing-at-point-looking-at pandoc-regex-in-text-citation-2)
          (funcall pandoc-citation-jump-function (match-string-no-properties 2) biblist))
         ((thing-at-point-looking-at pandoc-regex-parenthetical-citation-single)
          (funcall pandoc-citation-jump-function (match-string-no-properties 3) biblist))
         ((thing-at-point-looking-at pandoc-regex-parenthetical-citation-multiple)
          (funcall pandoc-citation-jump-function (match-string-no-properties 4) biblist))
         (t (error "No citation at point")))
      (error "No bibliography selected"))))

(defun pandoc-goto-citation-reference (key biblist)
  "Open the BibTeX file containing the entry for KEY.
BIBLIST is a list of BibTeX files in which to search for KEY.
The first file in which KEY is found is opened in a new
window (using `find-file-other-window').

This function is the default value of `pandoc-citation-jump-function'."
  (let* ((key-regexp (concat "@[a-zA-Z]*[[:space:]]*[{(][[:space:]]*" key))
         (bibfile (cl-loop for file in biblist
                           if (with-temp-buffer
                                (insert-file-contents file)
                                (re-search-forward key-regexp nil t))
                           return file)))
    (if (not bibfile)
        (error "Key '%s' not found" key)
      (find-file-other-window bibfile)
      (goto-char (point-min))
      (re-search-forward key-regexp nil t)
      (beginning-of-line))))

(defun pandoc-open-in-ebib (key biblist)
  "Open BibTeX item KEY in Ebib.
BIBLIST is a list of BibTeX files in which to search for KEY.

This function is for use in `pandoc-citation-jump-function'."
  (let ((bibfile (cl-loop for file in biblist
                          if (with-temp-buffer
                               (insert-file-contents file)
                               (re-search-forward (concat "@[a-zA-Z]*[[:space:]]*[{(][[:space:]]*" key) nil t))
                          return file)))
    (if bibfile
        (ebib bibfile key)
      (error "Key '%s' not found" key))))

(defun pandoc-show-citation-as-help (key biblist)
  "Show the BibTeX item KEY in a *Help* buffer.
BIBLIST is a list of BibTeX files in which to search for KEY.

This function is for use in `pandoc-citation-jump-function'."
  (let ((entry (cl-loop for file in biblist
                        thereis (with-temp-buffer
                                  (insert-file-contents file)
                                  (when (re-search-forward (concat "@[a-zA-Z]*[[:space:]]*\\([{(]\\)[[:space:]]*" key) nil t)
                                    (beginning-of-line)
                                    (let ((beg (point)))
                                      (goto-char (match-beginning 1))
                                      (forward-list)
                                      (buffer-substring beg (point))))))))
    (if entry
        (with-help-window (help-buffer)
          (princ entry))
      (error "Key `%s' not found" key))))

(provide 'pandoc-mode)

;;; pandoc-mode.el ends here
